Many commercial delivery companies employ trucks with roll-up side or rear doors to gain access to merchandise stored within the trucks. The roll-up door encloses a doorway leading into the cavity of the truck. At the bottom edge of the doorway is a sill. At the bottom of the roll-up door is a seal which conforms to the sill when the roll-up door is in the closed position. The seal is generally made of a solid rigid material such as rubber that will keep the elements out of the cavity of the truck but yet will not damage the sill when the roll-up door is being closed. A strap adhered to the interior wall of the roll-up door and extending beyond the bottom edge of the doorway aids an operator in lowering the door.
When closing the door, the operator will generally pull down on the strap. As the door is lowered, the downward velocity of the door increases. When the door nears the sill, frequently the operator will throw the strap into the cavity of the truck so that the strap does not extend outside of the truck to be exposed to the elements or to drag on the ground. An injury may occur if the operator does not act quickly enough and catches his hand or a portion thereof between the seal and the sill of the doorway. The velocity of the door results in such a force that injury to the hand and loss of fingers have occurred when the hand was caught between the seal and the sill.